Molecular Scaffolding with Tetrathiafulvalene—Design and Synthesis of New Molecules for Molecular Electronics

Abstract

Since the field of molecular electronics originated in the 1970s, the sulfur-containing heterocycle tetrathiafulvalene (TTF) has played a leading role. The reason for this is its ability to undergo two reversible one-electron oxidation steps at potentials that can be finely tuned by either peripheral substitution or by insertion of a π-conjugated spacer between the two dithiole rings. This review summarizes our own efforts in developing the synthetic TTF chemistry for obtaining a variety of molecules with potential applications in molecular electronics devices, such as redox-controlled molecular wires incorporating vertically disposed extended TTFs (cruciform molecules), conjugated macrocycles (dehydroannulenes) with fused TTF units, TTF-perylene diimide donor–acceptor dyads with broken conjugation, and redox-controlled dihydroazulene photoswitches. The synthetic strategies are to a large extent based on acetylenic scaffolding with acetylenic dithiafulvene and tetrathiafulvalene building blocks, employing different metal-catalyzed coupling reactions.